Extruder gearing

[Roxy]

Is there a reason why the Greg Wades extruder uses 9 & 47 tooth herringbone gears? Is this ratio the best or is it just what happened to be used? Thinking about replacing mine with a pair of GT2 pulleys, but those pitches aren't standard. I could make them myself out of aluminum if that gearing is the best, but if 10 & 50 would work that would make things easier.

The ratio can be anything that prints OK. I've been running a modified Wade's extruder for a couple of years. I wanted as low of gear ratio as possible. So I was scaling up the big gear and shrinking the little gear. It turns out, 9 teeth is pretty much at the lower end if you want the teeth to mesh nicely with the other gear. When you get below 9 teeth, the gear is getting small enough you start loosing a lot of strength too.

On the big gear... I actually moved the motor mount further away so I could scale up the big gear. I'm actually running a 9/76 gear ratio right now.